<template>

  <div class="app-container">

    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>

    <el-form label-width="120px">

        <el-form-item label="课程标题">
            <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
        </el-form-item>

        <!-- 所属分类 TODO -->
        <el-form-item label="课程分类">
        <el-select
            v-model="courseInfo.subjectParentId" 
            placeholder="一级分类" @change="subjectLevelOneChanged">
            <el-option
                v-for="subject in subjectOneList"
                :key="subject.id"
                :label="subject.title"
                :value="subject.id"/>
        </el-select>
        <el-select   
            v-model="courseInfo.subjectId"      
            placeholder="二级分类">
            <el-option
                v-for="subject in subjectTwoList"
                :key="subject.id"
                :label="subject.title"
                :value="subject.id"/>
        </el-select>
        </el-form-item>

         <!-- 课程讲师 TODO -->
        <el-form-item label="课程讲师">
        <el-select
            v-model="courseInfo.teacherId"
            placeholder="请选择">
            <el-option
                v-for="teacher in teacherList"
                :key="teacher.id"
                :label="teacher.name"
                :value="teacher.id"/>

        </el-select>
        </el-form-item>

        <el-form-item label="总课时">
            <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
        </el-form-item>

        <!-- 课程简介-->
        <el-form-item label="课程简介">
        <tinymce :height="300" v-model="courseInfo.description"/>
        </el-form-item>

        <!-- 课程封面 TODO -->
         <!-- 课程封面-->
        <el-form-item label="课程封面">

            <el-upload
                :show-file-list="false"
                :on-success="handleAvatarSuccess"
                :before-upload="beforeAvatarUpload"
                :action="BASE_API+'/eduoss/fileoss'"
                class="avatar-uploader">
                <img :src="courseInfo.cover" width="200px">
            </el-upload>

        </el-form-item>


        <el-form-item label="课程价格">
            <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
        </el-form-item>

        <el-form-item>
            <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
        </el-form-item>
    </el-form>

  </div>
</template>
<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'
export default {
    // 声明组件
    components: { Tinymce },
    data() {
        return {
            saveBtnDisabled:false,
            courseInfo: {
                title: '',
                subjectId: '',
                subjectParentId:'',
                teacherId: '',
                lessonNum: 0,
                description: '',
                cover: '/static/1.jpg',
                price: 0
            },
            courseId:'',
            BASE_API: process.env.BASE_API,
            teacherList:[],
            subjectOneList:[],
            subjectTwoList:[]
        }   
    },
    created() {
        if(this.$route.params && this.$route.params.id){
            this.courseId = this.$route.params.id
            this.getInfo()
        }else{
            this.getListTeacher()
            this.getSubjectOne()
        }
    },
    methods:{
        getInfo(){
            course.getCourseInfo(this.courseId).then(response=>{
                 //在courseInfo课程基本信息，包含 一级分类id 和 二级分类id
                this.courseInfo = response.data.courseInfo
                subject.getNestedTreeList().then(response=>{
                        this.subjectOneList = response.data.list
                        for (let i = 0; i < this.subjectOneList.length; i++) {
                            var subjectOne = this.subjectOneList[i]
                            if(this.courseInfo.subjectParentId===subjectOne.id){
                                this.subjectTwoList = subjectOne.children
                            }
                        }
                })
                this.getListTeacher()
            })
        }, 
        handleAvatarSuccess(res, file){
            this.courseInfo.cover = res.data.url
        },
        beforeAvatarUpload(file){
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2

            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
        },
        subjectLevelOneChanged(value){
            for(var i=0; i<this.subjectOneList.length;i++){
                var subjectOne = this.subjectOneList[i];
                if(subjectOne.id===value){
                    this.subjectTwoList = this.subjectOneList[i].children
                    //把二级分类id值清空
                    this.courseInfo.subjectId = ''
                }
            }
        },
        getSubjectOne(){
              subject.getNestedTreeList()
                .then(response=>{
                    this.subjectOneList=response.data.list
                })  
        },
        addCourse(){
             course.addCourseInfo(this.courseInfo)
            .then(response=>{
                //提示
                this.$message({
                        type: 'success',
                        message: '添加课程信息成功!'
                    });
                //跳转到第二步
                this.$router.push({ path: '/edu/course/chapter/'+response.data.courseId})
            })   
        },
        updateCourse(){
            course.updateCourseInfo(this.courseInfo).then(response=>{
                 //提示
                this.$message({
                        type: 'success',
                        message: '修改课程信息成功!'
                    });
                //跳转到第二步
                this.$router.push({ path: '/edu/course/chapter/'+this.courseId})
            })
        },
       saveOrUpdate(){
            if(!this.courseInfo.id){
                this.addCourse()
            }else{
                this.updateCourse()
            }
       },
       getListTeacher(){
           course.getListTeacher().then(response=>{
               this.teacherList = response.data.items
           })
       }
        
    }
}
</script>
<style scoped>
    .tinymce-container {
    line-height: 29px;
    }
</style>
